1. Field of the Invention
The requirement for thin plastic cards, so-called ID cards, is constantly increasing. Whilst major portions of these cards can be pre-printed with non-variable data, it is frequently desirable and economical to apply the variable data, such as name, expiration date etc., at a later stage with the aid of a printer, in which case it should preferably be possible to print on both sides of the card.
However, most printers are not capable of printing documents of the size of the usual ID card, which measures 21/8.times.33/8 inches. Therefore such cards are usually first of all fixed on a sheet of paper or a material web in continuous form before they are delivered to a printer for application of the variable data.
If the cards are applied directly to a carrier sheet with a contact adhesive, this means that only one side of the card can be printed at a later stage. Furthermore, as a result an overall thickness of the product is soon reached which is no longer accepted by all printers.
2. Description of Related Art
U.S. Pat. No. 5,403,236 discloses a card product in which these disadvantages are avoided by providing a cut-out into which the card is inserted in a first sheet, the connection of sheet and card being made for example by two adhesive strips on the reverse side of the card. In this case these adhesive strips only cover a small portion of the card.
In the production of this known card product the cut-out is first of all produced in the first sheet. Then the adhesive strips provided with contact adhesive are applied to this sheet in such a way that they overlap the cut-out with a part of their surface. Finally, in a last operation the card is inserted into this cut-out, so that it comes into contact with the overlapping part of the adhesive strips and is thereby secured in the cut-out.
When the card is inserted it must be aligned exactly with the cut-out. Such alignment is, however, always subject to deviations within a certain range of tolerance. Therefore, with this method it is imperative that the card has a length and width which is somewhat smaller then the length and width of the cut-out. Experience shows that in this case a difference in the length and width of approximately 50/1000 of an inch (1.27 mm) is necessary in order to compensate for deviations due to the insertion process.
Accordingly the card product produced using this method has gaps between the card and the sheet material surrounding the card which can vary between 25/1000 of an inch (0.635 mm) and 50/1000 of an inch (1.27 mm). Apart from an unpleasant aesthetic overall impression, such a card product can no longer be printed by offset or flexographic printing methods if the impression is also to be made in the junction region between card and sheet material, since the printing ink would collect in the gaps between card and sheet material and on the impression cylinder of the printing press. This in turn leads to unwanted inking on the card product and, in certain circumstances, to damage to the printing plate or the platen cylinder.